As disclosed in official gazettes published by the Japanese Patent Office, including JP-B-50-10284U, JP-B-5-36285 and JP-B-6-62134, a conventional filling and packaging machine for automatically filling and packing a material to be packed, such as liquid, powder and viscous material, is known to perform the steps of folding a continuously fed film, overlapping both edges of the folded film, longitudinally sealing the overlapped edges, filling a material to be packed into the longitudinally sealed film, laterally sealing the film, cutting a central part of the laterally sealed portions by a cutting mechanism to separate the film into individual packages, and delivering them out of the machine.
Such a filling and packaging machine is often constructed to form a longitudinal seal also at a central part of the film so that package bags containing a filled material are parallelly disposed side by side as they are delivered from the machine, and the machine often has a perforated line forming apparatus for forming a perforated separation line at the longitudinally sealed portion that constitutes a border between the left and right parallelly disposed package bags loaded with a material.
The conventional perforated separation line forming apparatus that forms a perforated line at a predetermined position on a transfer material (connected package bags), as described above, includes an edged rotary body (edged disk) simply having a round slitting edge and a receiving rotary body (receiving roller) having a receiving circumferential surface that the round slitting edge engages, with the transfer material held between these rotary bodies. The conventional perforated separation line forming apparatus has formed, in the receiving circumferential surface of the receiving rotary body, recesses (grooves) of a predetermined circumferential width for making non-slit portions at predetermined intervals in the direction of rotation.
That is, as the transfer material is fed, both of these rotating bodies rotate and the round slitting edge presses against the receiving circumferential surface to cut under pressure the transfer material at a predetermined position, while at the recesses the round slitting edge does not press against the receiving circumferential surface, so the transfer material is not by pressing.
Because the recesses are formed in the receiving circumferential surface at predetermined intervals, circumferential widths of the recesses constitute the non-slit portions and circumferential distances between the recesses on the receiving circumferential surface constitute the slit portions. These non-slit portions and slit portions together form a perforated separation line.
In the example case where a perforated line is formed in a longitudinally sealed portion at the boundary between the left and right package bags, however, when the hardness or thickness of the longitudinally sealed portion changes as a result of a change made in the material or thickness of the film, for example, it will become more difficult or easier to separate the left and right package bags if the same perforated line is formed at all times.
That is, when the longitudinally sealed portion is hard and not easily cut, it is desired that the ratio of the slit portion to the non-slit portion be increased to make it easier to separate the longitudinally sealed portion.
Conversely, when the longitudinally sealed portion is thin and easily cut, it is desired that the ratio of the slit portion to the non-slit portion be reduced to adjust and lower the level of ease with which the longitudinally sealed portion can be separated.
In the conventional apparatus, however, to make such an adjustment on the slit ratio of the perforated line, it is necessary to prepare a plurality of receiving rolling bodies with different circumferential widths or formation pitches of the non-slit portion forming recesses and to replace the receiving rolling body. This replacement work is not only troublesome but very costly because different receiving rolling bodies must be used. This is not practical. Further, even when such a replacement is made, the replacement choice is limited to a fixed number of receiving rolling bodies separately prepared for replacement.
Hence, under the present situation, there is no alternative but to form a perforated line with a fixed ratio between the slit portion and the non-slit portion at all times (i.e., the slit ratio of the perforated line cannot be adjusted as required). This gives rise to a problem that, in the filling and packaging machine as described above, the level of ease with which the perforations can be separated may change as a result of a change made in the material or the like of the film.
The invention has addressed and solved these problems experienced with the conventional perforated separation line forming apparatus, and it is an object of the invention to provide a novel perforated separation line forming apparatus which is very practical and capable of quickly adjusting the ease with which the perforated separation line can be separated, with simple operations and little additional cost.